In recent years, a demand for high-resolution, high-quality video, such as HD (High Definition) video and UHD (Ultra High Definition) video, has been increased in various areas. As video data comes to have high resolution and/or high quality, an amount of video data relatively goes up compared with existing video data, and thus, when the video data is transmitted via a conventional wired/wireless broadband network or is stored in an existing storage medium, costs for transmission and storage are increased. To address such problems that occur as video data goes to high resolution and high quality, high-efficiency video compression technologies may be utilized.
A number of scheme have been introduced for a video compression, such as inter prediction scheme that predicts pixel values included in a current picture from a picture before or after the current picture, intra prediction scheme that predicts pixel values included in a current picture using pixel information in the current picture, and entropy encoding scheme that assigns a shorter codeword to a value that happens more frequently while assigning a longer codeword to a value that happens less frequently. Such video compression schemes may be utilized to effectively compress, transmit, or store video data.